Question

What are vampire numbers?

Answer 1

the numbers which have vompire
haha just kidding

Answer 2

Answer:

A "vampire number" is an integer with 2n digits that is the product of two n-digit numbers — the fangs — whose digits, when combined, form a permutation of the original digits (thus, multiplicity counts). The smallest vampire numbers are 1260 (= 21 × 60) and 1395 (= 15 × 93